Tolga ÓZTÚRK, Turgay AYKUT, University of Istanbul, Faculty of Forestry, and Hulusi ACAR, Karadeniz Technical University, Faculty of Forestry, Trabzon, TURKEY
Forest transportation should be considered in two stages. The first one is called primary transportation, which covers all activities from felling to the landings, and the second one is called secondary transportation, which covers hauling activities between landings and sawmills.
Timber haulage is a difficult, expensive and time-consuming operation, especially where the forests have drawn away up to the mountainous areas. The studies have been carried out with Koller K300 skylines used for timber haulage.
These studies were conducted in the harvesting areas of Salalet Tepe of Taşlica Forest District. The units of productivity of skylines are cubic metres per day and cubic metres per hour, and the expenditure of fuel in skylines litres per cubic metre. Productivity values have been determined as 5.676 m3 per hour for the Koller K300 skyline in the Salalet Tepe harvesting area.
The combination of forest roads with the mobile skylines is the most convenient method of transportation for the Artvin region. Short-distanced skylines will be a necessary supplement to existing forest roads in the future. Long distanced skylines should be borne in mind as a substitute for missing forest roads.
Key words: Forest transportation, Koller K300, time analyses, Turkey
The transport of forestry products is realized in two stages. The first one is the primary transport stage which involves the haulage of timbers, while the second one is the secondary transport stage involving the main stage of transport of timbers, generally realized by trucks on forest roads (Aykut, 1986).
In order to meet the needs of the community for wood as a raw material, as well as to ensure that products of higher quality reach the buyer in the shortest possible time, the methods of timber haulage to be employed in forests have been adapted to present technological developments. Thus, the timber haulage operations have been developed in parallel with the advances accomplished in mechanization, thereby ensuring the performance of haulage operations with increased safety. As a result, it has been possible to transport the hauled timber without any loss in quality and quantity.
The haulage of forest products represents the most difficult stage of transport operations. Therefore, the time studies carried out on timber haulage operations will help the realization of transport planning with no loss of time, as well as determine the wages to be paid to the workers in an equitable manner.
Forestry production operations in Turkey are carried out intensively during the late spring and summer months, while to a limited extent during the winter months. The haulage of timber produced, as well as other forestry operations, depends very closely on the weather conditions. Therefore, the rendering of time studies and the planning of operations on the basis of such studies bear great importance in order to be able to carry out the operations to be performed in the limited summer months in a more productive manner, and to complete the operations within the desired time.
Material and method
The equipment used in the application of the method employed in carrying out the time studies involved in this work are the time-study recording disc, time-study forms and chronometers (Aykut, 1972).
Koller K300 short-distanced skylines mounted on a form tractor with an engine power of over 50 HP were used in the study. The skylines were mounted on form tractors and were brought to the production area mounted on the tractors. The skylines were powered through the power take-off unit of the tractors.
The transport distance of the skylines is 300 m and the daily transport capacity is 30–60 m3 on average. The thickness of the main lines is 16 mm while the drawing rope is 10 mm in thickness and has a length of 350 m. The safety ropes are 30 m long with a thickness of 16 mm.
Four workers are employed in operating the skyline which weighs 1 500 kg excluding the tractor. The average drawing speed of the rope is 192 m per minute, and the height of the tower is 7 m. It takes 3–5 h to mount the skyline while the dismounting time is 1–2 h. The number of safety ropes ranges between 2 and 4 (Öztürk, 1997).
In this study, the method of continuous measurement of time was employed. The complete timber haulage operation performed in this study, using the skylines described above, consists of eight stages enumerated below. The time required for completion of each stage was measured by a chronometer.
The mounting and dismounting operations of skylines vary depending on the land characteristics, weather conditions and the technical features of the skyline. Since the time study involves the amount of timber hauled by the skyline each time, the mounting and dismounting periods were not included in the time study figures, but were added to the total period of time during which the skylines were in operation during the year. Calculations were based on 8 h of working per day, and the average yield values were calculated accordingly (Öztürk, 1997).
Results and discussion
In the district where this study was carried out, the location named Keçi Sirti represents the minimum elevation at 1 300 m above sea level. According to the measurements made in the production area, the average slope of land is 56 percent. The minimum slope measured 25 percent and the maximum slope 100 percent. The road density in the area is 14 m per hectare.
Taslica District, operating under the management of Artvin Forestry Operations, was chosen as the study area for timber haulage operations. In three different locations of the production district, Koller K300 skylines mounted on tractors were used (see Figures 1 and 2).
Figure 1. Length profile of Koller K300 skyline
Figure 2. Koller K300 skylines at the Salalet Tepe Production Forest
The average times of timber haulage for the Koller K300 skylines installed in three different locations in the district are shown in Table 1, while the share of time taken by each stage of the operation in the total time is shown in Figure 3.
As a result of measurements and calculations made during timber haulage operations, the maximum times were found to be required for bringing the loaded carriage up to the place of unloading, and for drawing the loading hook to the loading place. The forest products hauled were 4–5 m long spruce and fir logs.
Table 1. The average work time obtained in Salalet Tepe harvesting area with a Koller K300 skyline
|Number of trials||16||14||25|
|a)||Pulling up of the empty skyline carriage to the loading place (min)||0.32||0.25||0.41|
|b)||Coming down of loading hook (min)||0.39||0.13||0.19|
|c)||Pulling the hook to the log and connecting (min)||2.45||1.36||3.17|
|d)||Pulling the log to the skyline carriage (min)||2.02||0.38||2.50|
|e)||Taking the loaded skyline carriage to place (min)||3.17||2.50||2.41|
|f)||Coming down of the hook (min)||0.29||0.08||0.06|
|h)||Pulling the empty hook to the skyline carriage (min)||0.11||0.10||1.05|
|i)||Total Time (min)||10.52||6.09||11.05|
Figure 3. Work analysis in total time
Table 2. Data of the Koller K300 skylines
|Koller K300 skylines||Hourly productivity||Daily productivity||Fuel||Working days in year||Length of skyline||Logging distance||Average slope|
Table 2 shows that the yield increases with increase in slope and decrease in the distance of transport. While the number of days of working at normal capacity during a year is 200 days for the skylines tested in this study, the total number of days worked during a year was less than half of this number during the period of our experimental study.
The first and third skylines were mounted on Ford 5000 tractors and the second one on a 1180 DTH tractor. In operating the skylines, a total of four workers - one operator in the upper station, one worker at the loading station, one worker at the unloading station and one wireless operator in the lower station - were employed. All workers employed at skyline operations were housed in the barracks located within the forest area.
A 2 m wide corridor was opened for the operation of each skyline. The tower of each skyline, located at the upper station, was fixed by tying it to three trees with three safety ropes. In the lower station, the main line was tied to two trees, one behind the other.
In that district, production operations were carried out using three Koller K300 skylines for a total of four months, namely July, August, September and October, hauling a total of 2 124 m3 logs and 225 stere wood. The 94 percent of total production realized in the district were transported by the forest skylines.
Conclusions and recommendations
The results of this study have shown that the transport of forest products by mobile skylines operated in areas located in mountainous terrain, not accessible by forest roads, is a more permanent and efficient haulage method in mountainous forest land when combined with forest roads, since it enables side drawing, eliminates losses in quality and quantity, offers a comparatively short mounting and dismounting time, has an opening-to-production rate of 100 percent and enables transportation in both directions when required.
In the light of the results of this study, the following recommendations should be taken into consideration in order to ensure the performance of timber haulage operations in a more effective and productive way.
For the operation of a skyline on forest land, there must be an adequate quantity of wood raw materials in the haulage area. In the area where timber haulage is to be carried out, the forest skylines should be brought to the area and installed after production operations are completed and before commencement of the haulage operation. The mounting of skylines should not be done before completion of the production operations.
The skyline in the haulage corridor should first be used for the haulage of those forest products nearest to the skyline, and then for the haulage of products present in the strips to be formed at a distance of 20 m from the right and left sides of the skyline (Acar, 2000).
Skyline operators must definitely be permanently employed workers. This point is important in order to ensure productive working and the careful handling and maintenance of skylines by the operators. For more efficient operation of skylines, a minimum of two workers should be employed at the loading station. This would enable the tying of hooks to the load in a shorter period of time, thereby minimizing any losses of time.
The studies required to be carried out in the production area prior to the installation of skylines for mounting purposes should be realized by experts. Persons not specialized in skyline operations should not be employed for this purpose, as skylines have expensive pieces of equipment and they cannot always be immediately repaired on site.
The Forestry Operations Office must pay special care and attention in providing proper accommodation facilities to the workers and meeting their food, tools and equipment needs in order to enable them to work in a more secure and productive way in field conditions.
In order to prevent decrease in their efficiency and to reduce fuel consumption, the maintenance of machinery must be performed according to technical specifications and in a timely manner. An adequate number of spare parts should be maintained in order to prevent any loss of time in case of urgent maintenance and repair needs.
In areas suitable for winter cutting, the use of skylines should be widespread in order to increase the speed of timber haulage operations. In mountainous areas, as well as in areas where road construction costs are high, the use of skylines in timber haulage operations would be the most economic and convenient method.
The timber to be transported where the machine is located in the unloading station should be either piled in a place which does not interfere with the operation of the machine, or a loader should be provided near the skyline to transport the product to the required place.
Acar, H.H. 2000. Forest Skylines (Turkish). Karadeniz Technical University Publication No. 62, 168 pp. Trabzon.
Aykut, T. 1972. The constructions and methods on the time analyses (Turkish). Review of the Faculty of Forestry, University of Istanbul, Series B, Volume 22, Number 1, Istanbul.
Aykit, T. 1986. The Cables for Wood transportation in Forestry (Turkish). Review of the Faculty of Forestry, University of Istanbul, Series B, Volume 36, Number 1, Istanbul.
Öztürk, T. 1997. The possibilities of using skyline cranes in Artvin forests in Turkey. (Turkish). Review of the Faculty of Forestry, University of Istanbul, Series A, Volume 47, Number 2, Istanbul.